To provide a location detecting device capable of reducing errors as much as possible in the case of detecting the direction of movement of a movable body by a gyro and highly accurately detecting the location of the movable body.

In the case of detecting the location of the movable body from the distance traveled by the movable body on the basis of the number of rotations of left and right wheels 5 and 6 detected by encoders 1 and 2 and the direction of movement of the movable body detected by the gyro 3, the difference in the number of rotations between the wheels 5 and 6 is multiplied by the inverse number of the tread between the wheels 5 and 6 to obtain the amount of direction change dpe of the movable body. The amount of direction change dpj of the movable body is detected by the gyro 3. By a selecting switch 23, the amount of change dpe in direction is selected in a region in which an angular velocity is small, and the amount of direction change dpj is selected in a region in which an angular velocity is large.